The present invention relates to transducer assemblies, and methods for radiating and detecting energy over a controlled beam width.
Transducer assemblies employing piezoelectric elements which radiate and sense acoustical energy at ultrasonic frequencies are commonly employed in detection systems to monitor areas to be protected. Due to differences in the shapes and sizes of individual areas to be monitored, it is desirable to be able to control the beam width over which energy can be radiated and detected by such transducer assemblies. Heretofore, it has generally been necessary to employ external reflectors or focusing surfaces in order to achieve such beam width control. An example of such a transducer assembly employing external reflecting surfaces is illustrated in assignee's copending U.S. patent application Ser. No. 471,280, filed May 20, 1974, entitled "PIEZOELECTRIC TRANSDUCER ASSEMBLY AND METHOD FOR GENERATING A CONE SHAPED RADIATION PATTERN."